Restriction of hazardous substances by statutes such as the Directive on the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment 2002/95/EC (commonly referred to as the Restriction of Hazardous Substances Directive or RoHS) was adopted in February 2003 by the European Union. The state of California has passed a similar law. The directive restricts the use of six hazardous materials in the manufacture of various types of electronic and electrical equipment. The six hazardous materials include Lead, Mercury, Cadmium, Hexavalent chromium (Cr-VI or Cr6+), Polybrominated biphenyls (PBB), and Polybrominated diphenyl ether (PBDE).
Industry seeks efficient and economical measures to comply with RoHS. Dissolution in acid is commonly used to test and measure compositional qualities of sample material. This method has inherent disadvantages. Laser induced breakdown optical emission spectroscopy (LIBS) as well as other laser spectrometry methods are potentially efficient and economical techniques to determining and/or verify the composition of products and other materials.
Isotopic analysis of sample composition can provide important information, particularly in the fields of archaeology, ecology, nuclear forensics, geology, hydrology, paleoclimatology, and national security, among others. Isotopic analysis has typically been done using techniques gas chromatography/mass spectrometry (GC/MS), time of flight mass spectrometry (TOF-MS), or inductively coupled plasma mass spectrometry (ICP/MS). Mass spectrometry (MS) is a powerful technique for isotopic analysis owing to its ability to discriminate ions based on mass to charge ratio. MS techniques can also be quite sensitive. However, these measurements often require time consuming counting and/or complex chemical digestion procedures for the mass spectrometric analysis. In general, mass spectrometric analyses must be performed in a vacuum, have low throughput, and require a gaseous sample.
Various other techniques that have been used for isotopic analysis include inductively coupled plasma-atomic emission spectroscopy, atomic absorption spectroscopy, and gas chromatography-atomic absorption spectroscopy. Each of these techniques has serious limitations and many of them require extensive sample preparation and/or dissolution in a liquid prior to analysis.
The LIBS type of spectrometry has been an unreliable and inexact measurement system since there is a large variation in the recorded data. A major source of variability has been inconsistent plasma plume generation by the pulse laser. Former LIBS type analyses have been unsuccessful in matching known standards achieved with other analysis methods.